In marine settings, anthropogenic disturbances and climate change increase the rate of biological invasions. Predicting still undescribed invasive alien species (IAS) is needed for preparing timely management responses. We tested a strategy for discovering new potential IAS using DNA in a trans-equatorial expedition onboard RV Polarstern. During one-month travel, species inside ballast water experienced oxygen depletion, warming, darkness and ammonium stress. Many organisms died but several phytoplankton and zooplankton survivors resisted and were detected through a robust combination of individual sampling, DNA barcoding and metabarcoding, new in ballast water studies. Ammonium was identified as an important influential factor to explain diversity changes in phytoplankton and zooplankton. Some species reproduced until the end of the travel. These species tolerant to travel stress could be targeted as potential IAS and prioritized for designing control measures. Introducing resistance to travel stress in biosecurity risk analysis would be recommended.

在海洋环境中，人为干扰和气候变化增加了生物入侵的速度。为了及时制定应对措施，需要预测仍未描述的外来入侵物种（IAS）。我们在RV Polarstern的跨赤道探险中测试了使用DNA发现新的潜在IAS的策略。在一个月的旅行中，压载水中的物种经历了氧气的消耗，变暖，黑暗和铵胁迫。许多生物死亡，但浮游植物研究中新发现的个体采样，DNA条码和元条码的强大组合可检测到许多生物死亡，但一些浮游植物和浮游动物幸存者抵抗并被发现。氨被认为是解释浮游植物和浮游动物多样性变化的重要影响因素。一些物种繁殖到旅行结束。这些能够耐受旅行压力的物种可以作为潜在的IAS来确定目标，并优先考虑设计控制措施。建议在生物安全风险分析中引入对旅行压力的抵抗力。